The present invention relates generally to resonators and, more particularly, to a high Q RF-MEMS resonator and a method thereof.
A high Q mechanical resonator is a device which is used to pass frequencies which are very close to the resonant frequency of the mechanical resonator. As disclosed in xe2x80x9cLarge Jobs for Little Devicesxe2x80x9d Stephen Cass, IEEE SPECTRUM, Jan. 2001, pp.72-73, which is herein incorporated by reference in its entirety, these high Q mechanical resonators are being operated in the 100+ MHz range.
Unfortunately, there are some problems with the existing high Q mechanical resonators. For example, the performance of these prior high Q resonators has been limited by stiction forces. Additionally, the upper frequency range of these high Q resonators is low restricting their use for some applications. Further these high Q resonators are difficult to fabricate and have a relatively large mass.
A resonator in accordance with an embodiment of the present invention includes a member with an embedded charge, at least one input electrode, at least one output electrode, and at least one common electrode. The input and output electrodes are spaced from and on substantially opposing sides of the member from the common electrode. At least one of the member and the input and output electrodes is movable with respect to the other.
A method in accordance with an embodiment of the present invention includes providing a member with an embedded charge, providing at least one input electrode, providing at least one output electrode, and providing at least one common electrode. The input and output electrodes are spaced from and on substantially opposing sides of the member from the common electrode. At least one of the member and the input and output electrodes are movable with respect to the other.
A method for passing a signal with a resonator in accordance with an embodiment of the present invention includes receiving an input signal at a resonant frequency for the resonator. A first varying signal is applied on at least a first pair electrodes in response to the received input signal. Each of the first pair of electrodes is spaced from and on substantially opposing sides of a member with an embedded charge. The member oscillates in response to the applied varying signal on the first pair of electrodes. A second varying signal is applied on a second pair electrodes in response to the oscillating of the member. An output signal is transmitted based on the applied second varying signal on the second pair of electrodes.
The present invention provides an rf-MEMS resonator which avoids many of the problems with existing high Q resonators. For example, the present invention avoids the prior problem with stiction. Additionally, the present invention is much simpler to fabricate, can operate at higher frequencies, is more robust, and has a higher reliability than prior resonators. The present invention can be used in a variety of different applications and can be used in a number of different products, including cell phone filters, wireless filters in general, high frequency filter networks.